The present invention relates to a vehicle suspension apparatus with a height control function for adjusting a vehicle height to a predetermined value and a position control function so as to forcibly correct changes (e.g., rolling and pitching displacements) in position of a body.
There is a way to control rolling of the vehicle body by providing fluid spring chambers in each of the wheels respectively. When the vehicle travels straight, the left wheel fluid spring chambers communicate with the right wheel fluid spring chambers to keep them at an identical pressure. However, when rolling control is to be performed, the left wheel fluid spring chambers are disconnected from the right wheel fluid spring chambers, and a predetermined volume of fluid is supplied to the fluid spring chambers which are contracted with respect to the rolling direction and at the same time a predetermined volume of fluid is exhausted from the fluid spring chambers which are extended, thereby controlling the rolling displacement of the vehicle body.
In order to achieve the above technique, mutual communication between the right and left fluid spring chambers and supply/exhaust of the fluid with respect to the corresponding spring chambers must be controlled. Therefore, the numbers of fluid paths and valves are increased, thereby complicating the control system.